Boundaries of Definition
by JasNutter
Summary: It was a treacherous time and Leo had seated himself at the heart of it, as he always did. Zo can only wait for him, and do as he's wished to.
1. Chapter 1

_A/N: Because I scoured every bit of the internet looking for Zo/Leo and came up with absolutely nothing, and thought someone should write it. Then I realized I was someone. And so here it is. This is going to be fairly long and fairly plotty, and fairly AU (only because it doesn't follow cannonical events though). Written just for fun while we wait for Tom's pretty, pretty face to reappear on screen. Don't own anything, as much as I wish I did. Enjoy..._

* * *

It was a day like any other: Florence was cheerful and charming as ever, as though no political turmoil plagued it; the streets were crawling and noisy as usual, and as usual, Leonardo was nowhere in sight, just as he was needed.

Well not so much needed as sought after. Zoroaster stumbled on a stray log and scowled, just barely dodging a stout man with a fruit basket. Cursing, he freed himself from the clutches of the market and finally spotted his friend seated on stone steps, lost in thought. Zo hurried towards him.

"I've been looking for you _everywhere_", he panted.

"Well, clearly not everywhere", Leo muttered back vaguely, not looking at him, not even stirring. Zo felt mildly irritated.

"Lorenzo's arrived asking for you", he informed, and at this, Leo did stir inquisitively. "Sais he won't leave until he speaks with you. Very agitated, something massive up his arse…What did you do?"

"Why must you always assume I've done something?" Leo deadpanned, getting to his feet, and grinned at his friend's pointed look.

"Any number of things", he conceded, walking around Zo and towards the workshop he ought not to have abandoned in the first place. Not today, at least. But Leonardo, ever the hurricane, was already veering into the market at top speed. Zo trailed after, only realizing after a moment that he was being spoken to.

"…only natural that he grows worried", Leo was saying as they expertly maneuvered around two arguing peasants, and ducked out of the crowd. "Does he have that idiot brother of his with him?"

"No", Zo responded shortly. "Just him and his hissy fit, and those dogs that follow him everywhere."

"Giuliano follows him everywhere, yapping at his heels, begging for a treat."

Zo couldn't say he didn't agree, but things had been strange with the Medicis recently. But to think of it, most things had been strange recently.

"They've had a falling out since the old man died. I hear Giuliano insists he wasn't the spy", he said lowly, looking out for the hounds. There had been a man not two weeks prior, who'd been beaten mercilessly to death for 'disgracing the Medici name', not long after the equally macabre execution of an innocent messenger. Zo would never say it aloud, because self preservation was a first priority, but they were quickly turning into the same tyrants Florence was resisting. Leo, whose list of priorities didn't cover anything that even remotely resembled self preservation, would, and probably had already. More often than not, Zo feared for the artist's very life.

Leo's own fear, however, Zo knew, existed entirely in dreams and shadows, of things that may not have ever existed.

"Well he may not be as idiotic as I think him to be, then", Leo remarked gravely, and ducked past the clothes line Zo lifted up for him. "Treacherous times, my friend. Need as many open minds as Florence can wring out."

If there were troubles in Florence, the lack of open minds was the least of them. What was far more pressing, Zo thought as he followed Leo into the darkened workshop, was the sight of Lorenzo de Medici standing rigid as a poker, looking as though he was about to split a spleen. Leo didn't seem bothered in the least.

"Your Magnificence!" he grinned in greeting, absently handing his bag to young Nico, who looked as nervous as Zo felt. "To what do I owe the pleasure?"

Zo looked questioningly at Andrea, moving to stand beside him. Andrea shifted uneasily. Across the room, Lorenzo bared his teeth in a very painful looking smile.

"I asked for re-enforcement, Artista", he said in a strained voice. "You've been commissioned, heavily so, to produce more of your designs. And when I arrive to ask of your men the status of these weapons you're meant to be creating, I'm informed there have been _no_ orders – _not a single mention_ – of making new weapons."

Leo looked on expectantly, as though waiting for Lorenzo to make his point. Zo could hardly suppress a groan. _Damn him_.

Lorenzo seethed, and looked as though he might breathe fire. "What is the meaning of this, Da Vinci", he hissed, stalking forward until he and Leo were nose to nose. Unfazed, Leo shrugged.

"I'm getting to it", he said casually.

Zo wanted to punch him. And so did Lorenzo evidently, for he emitted a choked noise and his hands twitched.

"Getting to it", he breathed incredulously, running a palm through his receding hair in frustration and stepping back. "Getting to it…_for god's sake,_Leonardo", he snapped. "I ride out to meet Riaro in a day's time with no additional defense than what's already of his knowledge, and you live your indolent arse off the commissions _I _have provided you, and say '_I'm getting to it?'"_

Leo shrugged flippantly. 'It's hardly my fault you can't rein in your brother's stupidity".

Nico gasped loudly, and before Zo could even fully wrap his head around the gall of the man, there was a flurry of movement, and Leo was pinned, not for the first time, against the wall, Lorenzo's hand around his throat. Without thinking, Zo moved towards them, and was immediately rebuffed by the guards, who turned on him instantly, swords glinting dangerously. Andrea pulled him back.

"Do not provoke me", Lorenzo ground out. Leo struggled, and was slammed back onto the wall again. He grimaced in pain. Zo flinched. "You will build these weapons, and you will have them ready by the time I set out, or I'll have your head, and I'll do it myself."

He let go, and Leo slumped against the wall with a grunt of pain. Zo made a move to help him up, but Andrea held him back, his grip unrelenting. He heard Nico swallow anxiously behind them. For a moment the only sounds were of Leo coughing, and Lorenzo breathing heavily. He then turned abruptly, and the swords withdrew. Nico rushed to the aid of his Maestro.

"You will do well to remember, Leonardo", Lorenzo said, stopping at the door, sounding completely composed now, "that you are no more than a lowly bastard. Your loss will be no great loss. Finish what you've started, before I finish you."

They watched them march out in complete silence, and stood in complete silence even after they'd left, staring after their red swaddled backs. Andrea was the first to break the quiet.

"Oh, Leonardo", he sighed wearily. "What have you done now?"

Leonardo stood, touching his neck lightly, looking slightly dazed. He straightened up.

"Tavern", he announced wheezily.

* * *

The Barking Dog was bustling with rowdy drunks and tired travelers alike, and Vanessa moved back and forth amongst them. Nico's eyes idly trailed her movements, and Zo wanted to smack him out of it. He refrained, sourly chewing his meat instead. Leo scribbled aggressively.

"Maybe you _should_ see a physician this time?" Zo advised.

"I'm fine", Leo said shortly, not looking up.

"What are you doing anyway?" he asked, looking over Leo's cup of wine at the sketches. "Are those – _pomegranates?"_

"Very good, Zo."

Zo wanted to cry.

"Lorenzo's _blade_ is at your throat, and you're here sketching fucking _pomegranates_."

Leo gave a noncommittal grunt.

Zo pushed his plate away violently, almost knocking over his friend's wine, and slumped back in his chair, his stomach in knots. Leo looked up at him incredulously, with the audacity to look affronted. There was no reasoning with the maniac. He crossed his arms and glared.

"When Lorenzo's got you hanging by your prick and is about to behead you, I'll just fucking let him", he threatened viciously. Beside him, Nico shifted warily, ripping his gaze away from Vanessa's behind. Leo looked taken aback.

"You wound me Zo", he said, mock sadly. "I was hoping you'd come rushing to my aid and carry me off in your arms like a proper princess and –"

"_God, fuck you",_Zo interrupted furiously. "Are you fucking suicidal, Leo? Is that fucking it? Because there are easier ways to die you goddamn clot. Save us all the fucking worrying."

"There's no need for invective" Leo said lightly. And then sighing under Zo's glare, he added, "Look, I have a plan, alright?"

Nico leaned forward eagerly while Zo groaned. "What plan, Maestro?" he asked.

Leo leaned in as well, very conspiratorially and very dramatically, and Zo, despite himself, was instantly curious. It wasn't enough for the man to be fucking brilliant at everything; he had to possess the best damned flair for drama as well.

"I think we can all agree", he started, so softly that Zo was compelled to lean in as well to hear him, "that old Beci, long dead now, was not in fact the spy."

He paused as Nico nodded his accent, and Zo grunted it. Having had skulked around the dregs of Rome for most of his life, Zo knew what spies were, and Beci had been as much of a spy as he had been a heretic.

"In that case, we can all agree that the spy is still at large, masquerading about as someone loyal to Lorenzo while underhandedly feeding Rome all his secrets. A person in direct contact with Lorenzo, and someone he trusts", he paused again; the familiar cheeky grin began making a slow appearance. "You see what's at play here, don't you? Lorenzo believes the traitor dead and not even his own brother can't convince him otherwise, which I don't find the least bit surprising, _but – ",_he raised a finger as Zo impatiently began to ask what this had to do with anything, " _but,_Lorenzo no longer guards state affairs as he would have in case of a scout, and why would he? Everything Lorenzo now knows, the spy knows, and ultimately, Rome knows."

Nico shook his head in puzzlement. "And why is that a good thing?" he asked.

"What are you up to now, Leo?" Zo groaned, suddenly a hundred times more apprehensive than he had been.

"Think. _Think!"_Leo exclaimed, eyes glittering. "When I promise Lorenzo fifteen more new innovations of mass destruction, one more destructive than anything Rome will ever encounter, and Lorenzo commissions me the sheer amount of florins that he did, don't you think he'd talk about it? Boast in the privacy of his council the enormity of Florence's new sting? Don't you think the spy, and in turn Rome, will find out? They probably have already. They're probably panicking as we speak!"

When one lived in company of Leonardo da Vinci, one lived in eternal trepidation. "Do you mean –", Zo was almost too afraid to ask."Do you mean you don't mean to make these weapons at all?" Nico stiffened at this, and looked wildly between Zo and Leo.

"No." Leo grinned like a mad man, and rocked back in his chair.

Zo felt his stomach drop to his bottom. "What did you do with the money?"

Leo shrugged. "I required it to buy metal for the apparatus I'm building."

Zo sat staring at him, reeling, uncomprehending. Nico emitted a little moan of despair.

"Oh my _God,_Maestro. What have you done?"

Leonardo huffed impatiently, and dropped his chair back onto all its feet with a clank. He took a swig of wine.

"Don't worry. I've worked it out."

Zo thought he might suffer a stroke. He snatched Leo's cup, took a great swig, and flagged Vanessa for another.

It was nearing curfew when he could bring himself to speak again, and Nico had long since taken leave. The alcohol had done nothing for his nerves, and neither had the sound of Leonardo's quill insistently scratching against paper.

"You're going to die. You're going to get us all killed."

Leo rolled his eyes. "I have a plan, alright, Zo. Please stop fussing. I'll need your help soon; will you endeavor not to worry yourself half to death?"

"You haven't just fucked Lorenzo on a deal", he said heavily, "but you intend to fuck Rome as well. With weapons that don't exist." He got to his feet angrily, and stumbled. His head was swimming. He sat back down and shut his eyes.

"And as though that isn't enough", he continued, suddenly feeling as though he might hurl. "You also have to be fucking that wench of a Mistress of his._Goddammit_ Leo."

Leo said nothing. Zo opened his eyes to find him peering at him curiously.

"What?"

"I just wonder sometimes", his friend smiled one of his beautiful, wondering smiles, "what it is you have against Lucrezia Donati, Zo. Why do you dislike her so much, when you've never even met her?"

It was envy. It was envy burning like the hell fires in his chest, and he would never admit it. "I think everything is off about her", he mumbled.

"It is, isn't it", Leo said cryptically, and Zo didn't want to think about what he meant. "Or you're merely envious."

But of course he knew.

"Fuck you", he cursed halfheartedly as Vanessa rang the bells, calling warnings of Dragonetti and his league of bullies. Leonardo got to his feet, and helped him to his, his fingers closed around his arms like the time they had when Leo had been under him, writhing and gasping in ecstasy.

The thought of Lucrezia that cropped up as they staggered through the passages was very unwelcome. He scowled.

"Jealously isn't fetching on you, Zo", Leo said, depositing him onto his bed. "Not fetching at all."

He left.

Zo slept fitfully, and wished he'd downed all the liqueur that existed.


	2. Chapter 2

_(A/N: Did I mention the heavy canon-borrowing? Because there's going to be a lot of that. Also, this doesn't fit into the timeline at all. It's written around the details but it doesn't really follow cannon.) _

* * *

"Twenty soldi, and no more", the old sculptor from Verocchio's workshop quibbled relentlessly, turning the stone over in his palms again and peering at it. He was half-deaf and mostly blind, and the stench of stale wine and pallid flesh clung to him like perfume. Zo, whose head was pounding as though it'd been smashed in to begin with, was desperate to get rid of him.

"Thirty", he stated firmly, and interrupted as his customer made to argue. "You'll never find any deal better for a stone such as this one for such a price. You'd have to pay hundreds." It was, in fact, just a curious looking rock, one of the many that he'd procured from the mudflats of Tiber while passing through Perugia. Smoothened by the water and sun, they had a mysterious allure, with white swirls decorating their surfaces. Zo claimed they protected against all kind of sickness, and the older Florentines were none the wiser. It had been a good venture.

The old man paid his soldi, grumbling, scooped up his stone and shuffled off to the workshop, nearly colliding with a cloaked lady that emerged from somewhere within in a great rush. The train of her rich gown followed her, as did Zo's dark gaze, and she took no notice. He glowered after her; there were only two reasons for her to be skulking about at this hour, and the reason clearly wasn't Lorenzo.

"Quite too early for a mood so foul", Leo remarked, emerging not long after his lover while Zo was still counting coppers. It was far too early for anything, in fact. The sun had not yet risen, the moon still hung like a pale limestone in the twilight. Vendors would arrive soon, derailing customers with cheaper and potentially more charming items – competition Zo would rather not bother with, unless a more lucrative opportunity presented itself.

"Business goes well, I see," he said and didn't wait for an answer, gesturing for Zo to walk with him instead. He walked off without waiting for Zo to collect his things. Zo cursed, and jogged to catch up.

"What?" he asked.

Leo produced a sheaf of papers, handed them over, and returned to rummaging the contents of his case. Zo flipped the writings over – a bizarre list of items, and even more bizarre designs of… Zo hadn't the foggiest what they were.

"Aluminum, sulfate, potassium nitrate…" he read through the list. "You plan to construct these weapons now?"

"Don't be absurd, those amounts would be nowhere near enough", Leo responded, his voice sounding muffled. Zo looked up to find his friend, much to his surprise, suddenly heavily bearded. He had donned a wig and was now arranging it around his face. Zo stared.

"What are you doing?"

"A disguise I recently perfected", Leo said. "Get those items, won't you? Nico's still abed, but you might want to wake him to assist you. Oh, and tell Verrocchio to employ as many as he can spare on building these…stage props, if you will. Have it done by nightfall, I should ride back by then", he pulled off his top coat and thrust it at Zo.

"Where are you going?" Zo asked confusedly, throwing the leather over his shoulder.

"In the near vicinity of Sienna", he said, then frowned. "Well I hope so." He clasped his cloak, drew the hood, and clapped Zo in the back. "I'll be taking your horse, if you don't mind."

Zo watched him rush off, and turned back to the frantically constructed shopping list. He hoped Verocchio would have more luck deciphering it than he did.

* * *

"Are you very certain, Andrea?" Zo questioned very uncertainly, gazing up at the colossal contraption. Young apprentices toiled endlessly, and it was still incomplete. "A giant crossbow. Are you sure?"

Andrea shrugged wearily. 'I've questioned that of myself the entire day, believe me."

"What use could a giant crossbow be to anyone?" Zo asked no one in particular. The said crossbow was more of a giant boat on wheels with a crossbow at one end, and they'd had to build it outside due to its epic proportions. On the far end of the courtyard, Nico and several others were hard at work, enclosing plaster molds twice the size of their heads in metal casings.

"I've learned to stop questioning his motives; I advice the same to you, lest you go mad". Andrea gave the ridiculous crossbow one last look and sighed. "Well, if he does return today, tell him the gunpowder is in his workshop, wont you? I shall retire for the night."

The hour was past midnight when the last wheel had been attached and the last mold wrapped and harnessed, but Leo had yet not returned. They had retreated into the workshop, waiting for him by the entrance, from where they could guard the giant contraption from dangers that Zo knew would not come. What would anyone want with a goddamn stage prop? But Nico had insisted.

"Where's he gone to anyway?" The boy questioned for the hundredth time, tiredly kicking at the remainder of the wood. Zo was sat against the wall, face buried in the top coat Leo had left behind. It smelled strongly of kerosene and paint.

"Wish I fucking knew", Zo answered. He was beyond anxious by now, and the anxiety made him irritable. "Somewhere in Sienna."

Nico looked at him curiously. "Why Sienna?"

"Wish I fucking knew", Zo repeated, and idly lobed a piece of shaved wood at the boy. It got caught in his hair, comically dangling off of one end. He flicked another, drawing a scowl and a _'stop that'_. Another hour and he'd start throwing the remainder of his fancy river stones.

Thankfully for Nico, another hour never came to pass, for Leo galloped home, un-bearded and un-cloaked. He shed his fake hair – at which Nico was gaping – cast it aside and clapped once in enthusiastic approval of the device his eyes suddenly fell on.

"Ah, it's done!" he exclaimed and strode out to where it stood. "Good. Good."

They followed him into the cold wind that tugged at Zo's clothes insistently, watching Leo as he bounded up the makeshift staircase. All irritation Zo harbored was rapidly giving away to a furious urge to pull the man in a relieved embrace.

He resisted, however, and, in the sourest voice he could muster, said, "Where in the fuck have you been? Nico's been crying for you."

Nico, who was in the middle of pulling on the wig, gave him a glare. "I have not!"

Paying no heed to them both, Leo rocketed about on the massive crossbow, inspecting. Zo watched in silent admiration as he tapped and examined, fingers twitching in concentration, the fire from the torch throwing his face in sharp relief. It seemed their worry that it would fall apart was unfounded, because Leo bounced about upon it, testing, and it failed to give away.

Leo halted suddenly and stared across the dimly lit courtyard at the pile of orbs he'd had them built.

"Perfect", he said distantly, as though his mind were elsewhere completely. "Perfect."

He looked at Zo, eyes glinting in the low light, and Zo felt as though his stomach had disappeared.

"Well, gather your men, Zo. I've got more work for you. Oh, and the gunpowder? Where is it?"

* * *

Nico had been slumped against the wall and snoring for a while now, and Zo wished desperately to join him. He took comfort in the fact that the men, who he'd woken at the barest crack of dawn with bribes of coin and Medici favor, were not complaining. He might have lost his head if they were.

Leo stood beside him, silent and scheming. He seemed distressed and agitated, which was not unusual, but somehow it seemed this time, he was angry; his face drawn into a frown, lips tight. He was shivering slightly, and Zo suddenly remembered the coat he still held in his hands, and offered it to him. Leo jolted, not taking notice for a moment, before pulling it on gratefully with mumbled thanks.

Nico gave a loud snore.

"You think they'll be fooled by this?" Zo asked softly after a moment, making sure they were out of earshot of the men. They worked in a half-asleep daze, attaching harnesses to the device to roll it out at dawn, and probably wouldn't have heard anyway.

Leo gave him a side-long long. "Would you have been?"

Zo pondered it, and concluded that he would indeed have been. It was an ingenious scheme, there was no denying that, but Zo fretted nonetheless. Riario was a smarter man than these men, who were all invariably fooled and thus admiring. Riario was a smarter man than he. Zo groaned.

"I don't even want to consider the fate of Florence if this doesn't work", he said lowly. Consider Leo's fate. His stomach twisted painfully. "What happens when Rome's mercenaries _do_ attack?"

"They plunder the city, kill us all, destroy as much as they possibly can", Leo stated matter-of-factly. "You needn't think of that right now."

"Easier said than done", Zo complained. His headache had returned with a vengeance. "You can't fucking_ fool_ everyone forever."

"Can't I?" Leo said, his gaze searching as though for assurance that Zo could not give; not when Zo was the one in need of assurance.

"Florence would have a fighting chance", Zo insisted, "with the weapons you design. Why won't you build them?"

Leo gritted his teeth and grimaced. "_God, _Zo," he spat acidly, "war isn't merely waged with a couple of thousand men on their horses and a couple of damned weapons to hopefully blast off as many heads as they possibly can. By the time these weapons will have to be used Florence will already have lost!"

Zo drew away, taken aback, and glanced at the men. A few of them were looking over curiously. Leo shifted uncomfortably, glanced at them as well, and lowered his tone apologetically.

"Florence is at war with Rome _already_. Perhaps it has always been – spies, crawling all over this place, all over Lorenzo's court, all over my workshop. Innocent Florentine men murdered in the name of justice." A pregnant pause followed as Zo pondered his words. "The point is not winning the war, it's stopping the war from happening and on this front Florence is already losing. Politicians will always be at each other throats, but it's the common man's throat they rip out while they're at it."

They fell silent, and Zo felt a rising sense of hopelessness. Nothing was merely black and white with Leo, there were shadows and grey areas and blurred lines and it was constantly unsettling, wrenching Zo out of his place of comforting certainty. They watched as the last of the harnesses were tied to the horses.

"We have Rome on the tenterhooks as of this hour, I'm sure", Leo murmured after a minute. "In a few, should this go as planned, they will be frightened beyond doubt – added what with the element of surprise we have in our favor. The point," he smiled faintly, "is not about fooling Rome, but fooling all the high born fools that name themselves leaders. The Medicis will be secure in their power, and the Papal States terrified out of their wits to approach with mercenaries. Which buys us time… and time is all, Zo."

Zo wasn't sure he understood; a feeling none too unusual. "Time for what?"

"To end the war already at large", Leo said firmly. "Because someone with half a brain ought to, and we all know brains are not common in the house of Medici."

Nico gave a mighty snore and woke himself up. Zo watched inattentively as the boy scrambled up blearily, dusting himself off, and wished again that he was in bed with Leonardo safe beside him, with no war to plague the both of them.


End file.
